The Immune System: non specific defences

Question 1

define Non specific immunity

Answer 1

Mechanisms that protect the body against a wide range of dangers
Usually present from birth, innate

Question 2

define Specific immunity

Answer 2

Mechanisms directed specifically against one invader
Body adapts to learning and remembering specific antigens to build an immunological memory

Question 3

define Immunity

Answer 3

Specific defence mechanisms

Question 4

define Antigen

Answer 4

Anything that stimulates an immune response

Question 5

What are the 5 main non specific defences

Answer 5

Epithelial barriers
Phagocytosis
Natural anti microbial substances
The inflammatory response
Immunological surveillance

Question 6

What is the function of the non specific defences

Answer 6

First line of defence to prevent entry of microbes and other foreign material

Question 7

what are the Epithelial barriers

Answer 7

Skin and mucous membranes, nose hair, cilia

Question 8

describe how nose hair acts as an epithelial barrier

Answer 8

Filter system to stop larger foreign bodies being inhaled and entering respiratory tract

Question 9

describe how cilia acts as an epithelial barrier

Answer 9

Waft mucus and inhaled foreign materials towards the throat so it’s is coughed up or swallowed

Question 10

what are epithelial secretions

Answer 10

E.g. oral,vaginal, gastric
Are antibacterial and often acidic, containing antibodies and enzymes

Question 11

Describe examples of epithelial secretions

Answer 11

Sebum and sweat contain antibacterial and anti fungal properties

Question 12

what are Anti microbial substances

Answer 12

Saliva, lysozyme, Hydrochloric acid (present in gastric acid), antibodies, interferons

Question 13

describe how saliva acts as an antimicrobial substance

Answer 13

Washes away food debris to prevent bacterial growth
Contains antibodies, lysozyme and buffers to neutralise bacterial acids that promote dental decay

Question 14

describe how a Lysozyme acts as an antimicrobial substance

Answer 14

Antibacterial enzyme present in tears

Question 15

describe how a Antibodies acts as an antimicrobial substance

Answer 15

Protective proteins inactivate bacteria
Coat membranes exposed to the external environment

Question 16

describe Phagocytosis

Answer 16

Neutrophils and macrophages
Move to sites of inflammation and infection as they are attracted to chemicals released by invaders
Attack, digest, destroy
Release toxic chemical
Chemicals released alert immune system

Question 17

Characteristics of neutrophils

Answer 17

Short lived, destroy themselves with their toxic chemicals

Question 18

Characteristics Macrophages

Answer 18

Live longer and link the non-specific defences with specific immunity

Question 19

define the Inflammatory response

Answer 19

Physiological response to tissue damage

Question 20

Describe inflammatory response, increased blood flow

Answer 20

Arterioles and capillaries dilate
So more oxygen provided to area
Increases temperature to specific area
Swelling and redness and temperature caused by local release of histamine and serotonin

Question 21

Inflammatory response accumulation of tissue fluid

Answer 21

More blood flowing means more water/fluid leaking out of blood vessels
Histamines and serotonin make capillaries’ walls more permeable

Question 22

Inflammatory response, migration of leukocytes

Answer 22

Blood left in blood vessels are thicker from loss of fluid/water, so flow is slower allowing white blood cells to attach to vessel wall to enter the tissues

Question 23

inflammatory response, increased core temperature

Answer 23

inhibits growth and division of microbes while promoting phagocytosis

Question 24

inflammatory response, pain

Answer 24

encourages protection, local swelling compresses sensory nerve endings

Question 25

inflammatory response, suppuration

Answer 25

pus formation, dead material (e.g. phagocytes, cells, living and dead microbes) are expelled out of the body

Question 26

natural killer (NK) cells

Answer 26

non-selective lymphocyte
patrol, searching for abnormal host cells
detected by displaying unusual markers on membrane
immediately kill abnormal cell